Although the website says that Sony Ericsson Handset supports up to 2GB, in reality it will support the 8GB or the 4GB card that you get. It will only be slow if you have a large number of files in one folder, regardless of the card size. For example, a 2GB card with 100 files in 1 folder would be slower than a 8GB card with 50 files in 1 folder because of the number of files that the phone has to load up.